Investors shouldn't expect to get off the roller-coaster ride in U.S. markets anytime soon, according to Wells Fargo's Brian Jacobsen.
The Wells Fargo Advantage Funds chief portfolio strategist said he believes the current bottoming pattern—if that is indeed happening in markets—may last beyond the Sept.16 and 17 Federal Open Market Committee meeting, at which central bankers will decide whether or not to raise interest rates.
"I do hope that it is a two to three week bottoming pattern. However, when I look at the history of bull market corrections, it actually suggests that it might take a little bit longer than two to three weeks," Jacobsen told CNBC's "Squawk on the Street."
Jacobsen said he projects the S&P 500 could trade "in a rather wide band" between 1,903 and 2,003 during the course of the next trading month, but overall volatility may last much longer.
"Sometimes the volatility is what really sticks around with us, and that could probably last anywhere from three to four months," he added.
Investors "live and die by beta" in this type of market, and they can find the risk they seek in small- and mid-cap stocks, information technology equities and the emerging markets.
That said, the emerging markets will be beset by political problems through the end of the year, so investors should be judicious about where they seek out opportunities in the developing world, Jacobsen said.
"Things in Brazil aren't getting any better. Things in Turkey are very unclear. Things in China, I think from a valuation perspective look pretty attractive, but there's still going to be I think huge moves in their markets, both to the upside and to the downside, that you're going to have to contend with," he said.
While strong August ISM nonmanufacturing data released Thursday favors the odds of a September interest rate increase, Jacobsen said the Fed wants to hike into both economic strength and stronger financial conditions.
"If financial conditions continue to stay tight over the next two weeks, I can't imagine that they would actually hike," he said.
However, a stock market move of 5 to 10 percent is unlikely to bother the Fed, Jacobsen added.